The overall goal of this project is to address the NCI need by developing and, for the first time, demonstrating relaxation-time-selective magneto-acoustic detection of functionalized iron oxide nanoparticles. Functionalized magnetic nanoparticles will be developed for specific aggregation at the tumor site. A nanoparticle-enhanced magneto-acoustic tomography (NEMAT) detection system will be designed and developed including the magnetoacoustic, and magnetic susceptibility measurement systems. A Phase I NEMAT prototype will be fabricated and assembled, and its operation demonstrated on phantom models. Final, the commercial promise of the NEMAT technology will be preliminarily established.